Breathing valves which interconnect a using device such as a gas mask to a source of gas to be breathed and then exhausted to atmosphere are known. For example, see Orland W. Wilcox U.S. Pat. No. 3,342,200, issued Sept. 19, 1967.
Such valves are frequently used under pressure strenuous and extreme conditions such as by miners and by firemen, as well as by pilots, and can become fouled with saliva and condensed moisture from the man's breath. Especially under cold ambient conditions, valves which utilize sliding and abutting valve workings can freeze up and stick. Also, when they dry out, they can become sticky. These of course are intolerable situations where a man's life may depend upon his ability freely to inhale and exhale.
Furthermore, it is commonly recognized that such valves ought to be quieter than they conventionally are. Especially when the person is working in quiet surroundings where his attention should not be distracted, clicks which occur whenever he inhales or exhales are very distracting, especially when he is using a microphone.
Accordingly it is an object of this invention to provide a breathing valve which is unlikely to stick even under most and cold conditions, and which operates reliably and silently.